Slippage permitting clamp



Feb. 19, 1935. b R. L. MccoY 1,991,690

SLIPPAGE PERMITTING CLAMP Filed Aug. 12, 1951 WW2-Q Patented Feb. 19,1935 UNITED ls'rn'rllzls VLearnit' snIPrAcE BERMITTING CLAMP tRobert L.McCoy, Baltimore, Md., assignorfto Locke Insulator Corporation,Baltimore, Md.,

a corporation of Maryland Application August' 12, 1931, seriarNatssis v2claims. 1 V(o1. aisfsl) I'I'he invention relates to clamps particularlydesigned for supporting the conductors of high tension transmissionlines. Y y

It is well known that it is customary to support transmission lineconductors by' means of strings of insulators suspended from towerslocated considerable distances apart. It 4frequently voccurs throughbreakage of the conductor or asthe result of an accumulation of ice or sleet on one or more clamps there are certain objections. "I-'o beginkwith-the conductor is notVPV of solid construction but comprises acore-about which arel wrapped or wound rods or wires usually of smallergauge than the core and formed customarily of aluminum. When the usualtype of releasing clamp opens upfthere is a certainy point at which theconductor will start to slip and itfrequently occurs that the breakcauses the exterior wires or rods to move relatively to thecore,`resulting in what is commonly called bird caging. Furthermore inthe use of the ordinary type of releasingclamp it is difficult topredetermine the exact holding power so that it may be known denitely atwhat degree of strain the clamp will open.

It is with the above facts in `view that I have devised the presentinvention which has forrits general object the provision of a conductorsuspension clamp of suchV constructionthat its holding power ispositively limited so that the cable may slip, without the clampopening, when a certain predetermined number of pounds'of pressure orstrain is exerted upon the conductor.

V.An important object of the invention is to provide a clamp of thischaracter which may be formed'of what are commonly considered standardparts with the simple addition of means cooperating with the clampingbolts for limiting the Y shown, in the customary manner.

vFigure 1. -member 21 are ears 23 apertured for the passage whichconstitute necessary parts of a`releasing clamp ofjtheV opening type..'Y

`Yet anotherobject is to provide'a clamp of this fol-#FICE characterv'which will be very simple and inexpent sive to make and assemble,positive in action, eincient and durable in service,v

provement in the art. v l

To-the attainment of the foregoing and other Aobjects and-advantages,the invention preferably consistsin the details of construction and thearrangement and combination of parts to Ybe hereinafter more fullydescribed andvclaimed, and illustrated in the accompanying drawing inwhich: Y l

*Figurev 1 "is aside elevation of .a clamp con# structed in accordancewith my invention, and

Figurev2 is a View half in end elevation andhalf in` section ontheline2-2 of Figure 1.

Referring more` particularly to the drawing I K `have shown: theV clampas comprising a main lower or body member. 1G formed with a curvedseat11 which extends longitudinally for the reception of the conductor,V notshown, the ends of the member Y10` being flaredor belled as indicatedat12 vand the ends ofthe seat being correspondingly ared or longitudinallycurved as at 13 for the purpose of avoiding bringing any bending strainson the conductor in the event of vibration thereof or what is known asdancing. At opposite sides the body member 10 is formed with laterallyvextend-V ing trunnions 14 with depending lips 15, the trun- `nions beingreceived within circular holes 16 in links 17 adapted to be bolted at 18`on to the lower end of a string of suspension insulators, not

The depending lip 15 prevents'accidental disengagement of the links fromthe trunnions but as an additional safeguard cotters 19 may be providedpassing through the trunnions outwardly ofthe links. Furthermore thebody member 10 is formed at opposite sides with pairs of laterallyextending ears'20. Y

Cooperating with and located above the body memberlO is the movableclamping member 21 which is formed with a transversely curved seat 22adaptedto contact with the conductor, this seat being moreoverVpreferably slightly longitudinally bowed as indicated by the dottedline in Projecting from opposite sides of the of clamping bolts 24 whichpass through holes 25 in the ears 20 and'which are equipped with springwashers 26 and nuts 27. While the washers could be omitted they providea certain re- 1,5. and a-general imj 2 l' y Y 1,991,690

wardly from their top sides and of course concen.

tric with the holes 25. Within these recesses are located bushings 29 ofany suitable metal and which have 'outstanding ianges 30 overlying thetops of the ears 20 and engaged "by thev undersides of the ears 23.

When the clamp is assembled upon'the conductorin an obvious manner andwhen the boltsl 24 are inserted and the nuts 27 applied thereto andturned up tightly it is apparent that the ilanges 30 located between theears 20 and 23 will limit the degree of clamping action exerted by themembers Y1() and ,2 1'upon the conductor. It Ywill be noted that theseats'll and 22 are rather grad-Y ually curved, the curvature being ofmuch greater radius than the radius of aconventional conductor. Byvirtue of this arrangement it is clear that the clamp may be used forsupporting conductors of different diameters. When a larger conductor isto be used or when it is desired to limit still further therpressureexerted bythe clamping members the idea is to usebushings 29 havingflanges 30 ofgreater thickness. In this way a clamp of one pattern suchkas that shown may vbe Vused in a large number of places and under widelyvarying circumstances by the simple expedient of having on hand a numberofinterchangeable bushings 29 with flanges 30 of difdiiferentycircumstances as regards the sizeof the conductor to be ysupported andthe degree of pressure lto be exerted thereon. The clamp is easily yassembled and applied and is of course used in exactly the same manneras any other of this type though it will be clear that when `the straincn the conductor at either side of a tower from whichV the conductor issupported by means of this special clamp exceeds a certain predetermineddegree the conductor may slip so that the unequal Y avoidingbringingexcessive strainsupon the tow# er such as might cause damage thereto. Itis thought from the above that the construction,

operation and advantages will be readily apparent vstrains at both sidesmay be equalized, thus l to one skilled-in the art without furtherexplana` Y;

Whilel have shown and described the preferred embodiment oftheinvention, it should be understood thatthe disclosure -is merely anexemplication of the principles involved vas the right is reserved tomake all such changes in the details Y v of construction as will widenthe field of utility V and increase the adaptability of the device pro?"vided such changes constitute -no departure` from the spirit of theinvention or the scopecffthe claims hereunto appended., v

Havingthus described the inventif-Jn,',lifclairn:

vmembersfcr securingthem-itogether in clamping engagement upon theconductor, andbushings surrounding said bolts and having anges locatedbetween the clamping members for limiting the holding power of thebolts. f 2

2. A conductor supportingV clampacomprising apairof clamping members-disposable upon-:op-i posite sides'of a conductor and equipped withsuspension means, said members having laterally;v

y v Vv extending ears, bolts passing through vthe correa .Y

in clamping'engagement Vupon :thej conductor;`

lspending ears for holdingtheclampingmembersY l certain of saidearsbeing-'formed v'vith'recesses;-V and bushings located withinsaid-recesses and'.r .l through which thebolts pass,said bushings ,havl

